1. Field of the Invention
This invention relates to tow rope handles used in various sporting activities in which a person is pulled at the end of a rope.
2. Background of the Invention
The conventional tow rope handle in use today for water skiing, knee boarding, wake boarding and other towed water sports, consists of a single straight bar connected to the tow rope by a V-shaped portion of rope. The standard grip a person uses for such a handle is called the baseball grip. The grip involves the user holding the top of the bar with one hand, defined as the top grip position, and holding the bottom of the bar with the other hand, defined as the bottom grip position. The baseball grip is widely recognized as permitting the greatest maneuverability for the user.
The top grip position will result in the person's arm being relatively straight with little bending of the elbow. However, the wrist will be flexed upward and the shoulder will be rotated toward the vertical mid-line of the user's body. The flexing of the wrist while being pulled causes strain on the wrist, which can cause injury. Some users of tow ropes wrap their wrists to provide additional support to combat wrist fatigue. The rotation of the shoulder also causes additional strain.
The bottom grip position of the baseball grip creates even greater biomechanical stresses. Specifically, the wrist is bent downward, the shoulder rotated away from the vertical midline of the body, and the elbow is bent. The reader will quickly discover this fact by gripping any straight elongated object using the baseball grip. Hence, the bottom grip has three biomechanical stress points, the wrist, the shoulder, and the elbow, when the person is under tow. Some users develop tendonitis in the elbow as a result and wrap the elbow joint to try to reduce the stress while skiing.
As a result of the differences in the biomechanics of the top and bottom grip positions, the user's power in controlling the bar comes from the triceps of the arm in the top position and the biceps of the arm in the bottom position. This causes several disadvantages. Since the user's tricep is invariably stronger than the user's bicep, the user's bottom arm becomes tired more quickly. This is further compounded by the fact that bottom position places the wrist and elbow in a bent position, which only adds to the stress from fatigue and torsion. A natural consequence of these factors is that the user experiences diminished control in the bottom arm relative to the top arm. Overall, the prior art device results in a reduction in the length of time that the user can engage in the sport due to fatigue. Also, the V-shaped portion of rope attached to the traditional handle is subject to uneven wear and tear due to the uneven loads placed upon each side of the handle for the reasons stated above.
The present invention addresses the shortcomings of the prior art because it is designed to biomechanically align the the shoulder, the elbow, and the wrist of each arm along a single axis. By aligning the joints in this manner, the stress is transferred to the muscles of the upper shoulders and upper back. These muscles typically have greater strength than the muscles of the arms. For this reason, they are less susceptible to fatigue. Additionally, transferring the stress to these muscles prevents injury to the wrist and elbow joints.
The present invention is able to achieve biomechanical alignment of the joints by primarily two distinguishing modifications to the prior art. First, the tow bar is bent at its midpoint. This results in a first and a second grip arm, each of which is angled downward from the midpoint. The user can hold the device with both hands in the top position without any loss of maneuverability, which typically occurs when a conventional straight tow bar is gripped with both hands in the top position. Furthermore, maneuverability is enhanced. The inventor has observed that 360.degree. spins are easier with the invention because the angled grips are in a more natural position to grasp when passing the tow bar behind one's back during the spin.
The construction of an angled tow bar has two biomechanical consequences. First, the elbows of both arms are able to remain straight since the bottom grip position is no longer required. Secondly, the shoulders are no longer rotated. For a person to hold an elongated object in a horizontal position in front of him or herself requires the rotation of the shoulder joint. By angling the first and second grip arms downward, the present device can be gripped without the need for rotation of the shoulder joints. This results in axial alignment of the elbow and shoulder joints. However, the wrist joints are still not in axial alignment with the other joints because they are still bent in an upward position.
It is the second structurally distinguishing feature of the invention that serves to bring the wrist joints into biomechanical alignment with the elbow and shoulder joints. Each of the angled grip arms has a terminal end at which a branch of the tow rope is secured. Additionally, at the midpoint of the tow bar, a third branch of the tow rope is attached. The third branch is sufficiently shorter than the other two branches so that the midpoint of the tow bar tilts forward when the tension is placed upon the rope. By tilting the midpoint forward, the wrists are no longer bent upward when holding the grip arms. Hence, the shorter third branch serves to bring the wrist joints into biomechanical alignment with the elbow and shoulder joints thereby permitting the stress of the tow rope to be transferred to the upper back and shoulders. Furthermore, since the handle has three support branches, each portion of the connecting rope's wear and tear is reduced from one half in the conventional model to one third in the present invention. The result is a more pleasurable sporting experience with less strain and fewer injuries.